A mesh network in which multiple wireless nodes are connected in a mesh form has been used. As a communication scheme for the wireless mesh network, a time-division communication scheme has been adopted, for example. The time-division communication scheme can facilitate control of the timing to cause each wireless node to sleep, thus allowing for energy-saving of the wireless mesh network.
However, the wireless mesh network has a problem that information transmitted by each wireless node is relayed by a plurality of wireless nodes to be transmitted to a root node, and thus it takes time to transmit the information to the root node.